ROBINSON MODEL R-44 HELICOPTER TRACK AND BALANCE

Transcription

1 Application Note AN-MV2-R44 Rev May 2012 MicroVib II Aircraft Analyzer Helicopter Track and Balance ROBINSON MODEL R-44 HELICOPTER TRACK AND BALANCE Dynamic Solutions Systems, Inc. (760) sales@dssmicro.com Applications Support (714) applications@dssmicro.com Product Support (760) support@dssmicro.com Training Support (715) training@dssmicro.com Rotor Track & Balance Equipment Requirements MFR P/N DESCRIPTION QTY REQUIRED M/R C/F T/R 1300 MicroVib II Aircraft Analyzer 1460 Accelerometer, 20mv/g X Accelerometer Bracket X Accelerometer Cable Accelerometer Bracket Magnetic Pickup 1170-X Magnetic Pickup Cable 1015 Photo-Tach 1520 Photo-Tach Bracket 1097-X Photo-Tach Cable 1254 Reflective Tape (roll) 1010 Rotor Protractor 1377 Electronic Scale 1428 Tab Tool Set, Universal MicroTracker Tracking Accessories 1145-X MicroTrak Optical Tracker x4 Signal Mux w/ Optical Adapter Strobe Tracking Accessories x4 Signal Mux w/ Strobe Adapter 1123 Strobe Power Cable C-H 135M-12 Strobe Tracker C-H 3387 Tip Targets PC Based Storage - Analysis - Reporting 1600 MicroBase Professional Software Serial Cable, MicroVib II to PC USB to RS-232 Adapter 1 Equipment Substitutions - See - products - equipment compatibilty AN-MV2-R44-1

2 I. Main Rotor Track And Balance Main Rotor Track And Balance Equipment Installation NOTE: When mounting vibration sensors, make sure that the vibration sensor s sensitive axis is aligned with the intended measurement direction. The sensitive axis always parallels the sensor mounting bolt axis. In some sensors, the electrical connector exits in-line with the sensitive axis, while in others, the connector exits at a right angle to the sensitive axis. Do not assume that the sensor s electrical connector orientation relates to its sensitive axis. A. Lateral Sensor: Attach the lateral vibration sensor to the center console using bracket The sensitive axis of the vibration sensor should point to the left as shown in Fig. 1. Connect and route cable 1096 to signal mux CH:1. B. Vertical Sensor: Attach the vertical vibration sensor to the standard RH location under an attachment screw on the left side of the instrument console using bracket The sensitive axis should point down as shown in Fig. 1. Fig 1 - M/R Lat & Vert Accels Connect and route cable 1096 to signal mux CH:2. C. Magnetic Pickup: If using a magnetic pickup and interrupter, install magnetic pickup in bracket on right side of mast as shown in Fig 2. Set mag pickup to interrupter gap to.050 in (1.27mm). Connect and route cable 1170 to signal mux CH:A. D. Photo-Tach: If using a Photo-Tach, attach the Photo-Tach to the aft (left) mast cowling using bracket The Photo-Tach should point up as shown in Fig. 3. Fig 2 - M/R Mag Pickup & Interrupter Connect and route cable 1097 to signal mux CH:A. E. Reflective Tape: Swing the main rotor until the Target blade is located at the front of the aircraft as in Fig. 5. Attach a 1 x 1.5 in. (25.4 x 38.1mm) piece of reflective tape 1254 to the underside of the blank blade grip as shown in Fig. 4. F. Photo-Tach Alignment: Power the MicroVib II and turn the rotor until the reflective tape passes through the photo sensor s light beam. When the tape passes through the beam, the photo-tach pilot light will illuminate to indicate Fig 3 - M/R Photo-Tach a valid reflection. The pilot light will blink at a rate proportional to the strength of the reflection. Fig 4 - M/R Reflective Tape G. Strobe: If using a Strobe, install tip targets on both blades. When installing tip targets, use care to insure that an equal amount of weight (i.e. tip targets, mounting hardware, etc.) is added to each blade. H. MicroTracker: If using the MicroTracker, attach the MicroTracker to the signal mux. Tip targets are not required when using the MicroTracker. AN-MV2-R44-2

3 Main Rotor Track And Balance Equipment Setup A. Download Latest Group File: For the best results, visit then download and install the latest R44 group file into your MicroVib II Aircraft Analyzer. B. Create New History File: Press MODE then CONTROL PANEL then NEW HISTORY FILE. Select the R44 group file and then press SELECT GROUP FILE. C. Modify History Filename: When you are prompted to modify the History Filename you must choose to either use the suggested filename or enter one which is easier to remember (such as the aircraft registration or serial number). When satisfied with the History Filename, press OK. The new History File will be automatically loaded into the Analyzer s memory. D. Verify Tasks: Select PROP ROTOR BALANCE and press START ANALYSIS. Press TASK and verify the appropriate tasks are available as shown in Fig 5. Task Conditions Collect Data Typical Data Use GND LT Gnd Run 100% Track Pattern Correct with PC Link Adjustment Lateral Vibration Correct with Mass or Headshift HOV VT Hover IGE Track Pattern Correct with PC Link Adjustment Save for reference only HOV LT Hover IGE Lateral Vibration Correct with Mass or Headshift 65KT VT 65Kt Level Flight Track Pattern Save for reference only Correct with Tab Adjustment 120KT VT 120Kt Level Flight Track Pattern Save for reference only Correct with Tab Adjustment Fig 5 - R-44 M/R Data Collection Tasks E. Main Rotor Definition: Refer to the main rotor depiction in Fig. 6 for locations and angles. F. Strobe Tracking: When checking blade track using a signal mux which supports strobe tracking, press TRACK OPTS and select TWO BLADE ROTOR followed by START ANALYSIS. G. MicroTracker Tracking: When checking blade track using a signal mux which supports the MicroTracker press TRACK OPTS and select TWO BLADE ROTOR. If desired, measure the distance from the MicroTracker operator to the rotor blade tips and enter that value in inches under SET TRACK DISTANCE then press START ANALYSIS. Refer to the blade order depiction in Fig. 5 to identify blades. H. Tip Weights: Suitable tip weights are A298-1, -2, -3 or -4 washers. Fine adjustment may be made by the addition of AN or -10L washers. I. Chordwise weight changes: (282 degrees) are limited by the chord arm weight capacity. Suitable chord arm weights are the following types: A255-2 weights grams, A255-1 weights - 52 grams, AN970-4 washers grams. The maximum number of chord weights that can be installed is two A255-2 or six A255-1 weights. NOTE: If a weight change is needed at 292 degrees and the amount of weight exceeds the capacity of the chord arm weight location, then a head shift move may me appropriate. When this is the case, use extreme care in interpreting the amount of head shift adjustment. A positive amount of head shift means to move shims away from the chord arm. A negative amount of head shift means to move shims towards the chord arm. Due to shim thickness, the minimum head shift move is 15 mils. AN-MV2-R44-3

4 Main Rotor Track & Balance Procedure A. Ground Tests 1. Select task GND LT. Run up the aircraft to 100% on the ground and check track. 2. Adjust the main rotor track using pitch link adjustment for the best ground track possible. Continue adjusting the ground track until blade spread is less than.5 in (12.7mm). B. Hover Track R-44 Main Rotor 1. Select task HOV VT. Hover the aircraft and check track. (viewed from above) 2. Make additional pitch link adjustments until the hover track is less Rotation TARGET than.5 in. (12.7mm). (360) C. Preliminary Hover Balance 1. Select task HOV LT. Hover the aircraft and collect lateral vibration (minimum 5 avgs). If the lateral vibration is above.2 in/s, correct the balance using Weight and/or Head Shift. Continue correcting the balance until the lateral vibration is below.2 in/s. 2. Select task HOV VT. Collect a vertical vibration reading for reference only. D. In-Flight Track NOTE: Note: RHC recommends making only down (negative) tab moves in order to prevent stick shake. 1. Select task 65KT VT. Fly at 65kts straight and level. Check track and collect vertical vibration (minimum 5 avgs). 2. Select task 120KT VT. Fly at 120kts straight and level. Check track and collect vertical vibration (minimum 5 avgs). 3. On the first vertical correction, you should generally make a trim tab correction based on the track picture. Enter the trim tab adjustment into both 65KT VT and 120KT VT tasks. Example: If the target blade (360) is high in the track picture and you bend the tab on the target blade down 1.0 degree - then on tasks 65KT VT and 120KT VT you will enter an adjustment of -1.0 at the target blade (360) location. Thereafter, the solution displayed will be in degrees of tab adjustment. Tip Weight Counterweight 4. On subsequent vertical corrections, you can utilize the displayed Figure 6 solution to adjust the tabs directly. The solution will always be split between adjacent blades. Press the SPLIT key to change the affected blades. 5. Repeat track and vibration readings using tasks 65KT VT and 120KT VT. Continue correcting track until vertical vibration is below.2in/s. Forward E. Final Hover Balance 1. Select task HOV LT. Hover the aircraft and collect lateral vibration (minimum 5 avgs). 2. If the hover lateral is above.2 in/s correct the balance using weight or head shift. Continue correcting the balance until the vibration level is below.2 in/s. (292) Reflective Tape (underneath blade cuff) Head Shift (90) Tip Weight Optical Tracker Blade Identification (tracker pointed forward) TARGET (180) Blank BLANK Mag Pickup AN-MV2-R44-4

5 II. Cooling Fan Balancing Cooling Fan Equipment Installation A. Vibration Sensor: Attach the Vibration Sensor to the standard RH location between the cooling fan blower housing and engine drive belt; using bracket The sensitive axis should point down as shown in Fig. 7. Connect and route cable 1096 to signal mux CH:3. B. Photo-Tach: Attach the Photo-Tach to the cooling fan shroud at the 5:00 position using bracket The Photo-Tach should point forward at the cooling fan as shown in Fig. 8. Connect and route cable 1097 to signal mux CH:C. C. Align Photo-Tach: Align the photo-tach so that the light beam is perpendicular with the cooling fan bulkhead and strikes the cooling fan at the 5:00 portion of its rotation. D. Attach Reflective Tape: Attach a piece of reflective tape 1 x 2 in. (25.4 x 50.8mm) next to one of the cooling fan mounting bolts as shown in Fig. 8. Choose the location carefully so as to insure that the tape passes through the Photo Tach beam as it rotates. E. Check Alignment: Verify the Photo Tach and tape alignment by powering up the MicroVib II and turning the rotor until the reflective tape passes through the photo sensor s light beam. When the tape passes through the light beam, the photo sensor pilot light will illuminate to indicate a valid reflection. Figure 7 - C/F Accelerometer Figure 8 - C/F Photo-Tach & Tape AN-MV2-R44-5

6 Cooling Fan Balance Equipment Setup A. Create New History File: If needed, create a new history file using the procedure from the Main Rotor Track and Balance section. B. Verify Task: Select PROP/ROTOR BALANCE and press START ANALYSIS. Press TASK and verify the appropriate task is available as shown in Fig 9. Task Conditions Collect Data Typical Data Use C/F BAL Gnd Run 100% Correct with Mass Adjustment Fig 9 - R-44 Cooling Fan Data Collection Task Cooling Fan Definition: Refer to the cooling fan depiction in Fig. 10 for locations and angles. Cooling Fan Balance Procedure NOTE: When using the rotor protractor to verify weight locations, the rotation arrows must be observed. This cooling fan turns counterclockwise so the protractor's blue side must be used. A. Ground Balancing R-44 Cooling Fan (Looking Forward) 1. Balance at 100%: Select task C/F BAL. Run the Rotation (270) Reflective Tape aircraft at 100% (~2720 C/F RPM) and stabilize. 2. Collect Vibration: Collect cooling fan vibration (minimum 10 avgs). (180) (360) 3. Adjust Weights: Adjust the rotor using the solution displayed in the Solution Calculator. 4. Enter Changes: Enter actual weight changes into the Solution Calculator. (90) Figure Repeat: Repeat until the vibration is below.2 in/s. AN-MV2-R44-6

7 III. Tail Rotor Balancing Tail Rotor Equipment Installation A. Vibration Sensor: Attach the Vibration Sensor to the 11:00 Tail Rotor Gearbox mounting bolt using bracket The sensitive axis point up as shown in Fig. 11. Connect and route cable 1096 to signal mux CH:4. B. Photo-Tach: Attach the Photo-Tach to the top rear edge of the tail boom using bracket The Photo-Tach should point to the left as shown in Fig. 11. Connect and route cable 1097 to signal mux CH:D. C. Align Photo-Tach: Align the photo-tach so that the light beam is parallel with the tail rotor output shaft and strikes the tail rotor when the blade passes through the 2:00 portion of its rotation as shown in Fig. 12. D. Attach Reflective Tape: Attach a piece of reflective tape 1 x 1.5 in. (25.4 x 35.4 mm) to one of the tail rotor blade grips. Choose the location carefully so as to insure that the tape passes through the Photo Tach beam as it rotates. E. Check Alignment: Verify the Photo Tach and tape alignment by powering up the MicroVib II and turning the rotor until the reflective tape passes through the photo sensor s light beam. When the tape passes through the light beam, the photo sensor pilot light will illuminate to indicate a valid reflection Tail Rotor Balance Equipment Setup Fig 11 - T/R Accel & Photo-Tach Fig 12 - T/R Photo-Tach & Tape NOTE: Verify which style tail rotor blades the aircraft is equipped with before balancing. Old style C029-1 blades use tip weights while the new style C029-2 blades utilize weights on the outboard retaining bolt. A. Create New History File: If needed, create a new history file using the procedure from the Main Rotor Track and Balance section. B. Verify Task: Select PROP/ROTOR BALANCE and press START ANALYSIS. Press TASK and verify the appropriate tasks are available as shown in Fig 13. Task Blade Type Conditions Collect Data Typical Data Use T/R BAL C029-2 (round tip) Gnd Run 100% Correct with Mass T/R OLD C029-1 (square tip) Gnd Run 100% Correct with Mass Fig 13 - R-44 T/R Data Collection Tasks C. Tail Rotor Definition: Refer to the tail rotor depiction in Figs. 14 and 15 for locations and angles. D. Tail Rotor Grip Weights: (360/180 deg) NAS1149F0432P, NAS1149F0463P, A214-3, A and AN970-4 washers. E. Tail Rotor Tip Weights: (360/180 deg) AN960-8, AN960-8L and C134-1 and C134-2 washers. Trim -8L washers for fine adjustment. F. Tail Rotor chord weights: (140/320 deg) AN , AN L and A washers. AN-MV2-R44-7

8 Tail Rotor Balance Procedure NOTE: When using the rotor protractor to verify weight locations, the rotation arrows must be observed. This tail rotor turns clockwise so the protractor's red side must be used. A. Ground Balancing 1. Balance at 100%: Select task T/R BAL (or T/R OLD if using the old style blades). Run the aircraft at 100% (~2310 T/R RPM) and stabilize. 2. Collect Vibration: Collect Tail Rotor vibration (minimum 10 avgs). 3. Adjust Weights: Adjust the rotor using the solution displayed in the Solution Calculator. 4. Enter Changes: Enter actual weight changes into the Solution Calculator. 5. Repeat: Repeat until the vibration is below.2 in/s. R-44 Tail Rotor (old style) TARGET 360 Fwd Rotation R-44 Tail Rotor (new style) TARGET 360 Fwd Rotation Weight Locations Reflective Tape (behind blade) Weight Locations Reflective Tape (behind blade) 140 ChordA ChordB ChordA ChordB 320 Weight Locations Weight Locations BLANK 180 Figure 14 BLANK 180 Figure 15 AN-MV2-R44-8